MSE testing status update

Hi Paul,

Sharing progress more widely, I have updated the MSE test result report
with Chrome M43's current MSE test results [1], following along the path
and instructions laid out most recently by Cyril [2]. I have also provided
some brief summarization to folks at Microsoft for how to update results
using the test runner and wptreport. If anyone needs those instructions, I
can share them here as well. They are essentially a summary of the
README.md's from w3c's test suite as well as wptreport.

Next steps will be to continue closing the test coverage gaps and updating
implementations (in my case, Chrome's implementation). Chrome, in
particular, would pass more of the existing tests if the
--enable-experimental-web-platform-features flag were used. I did not use
that flag when generating the test results.

[1] http://w3c.github.io/test-results/media-source/all.html
[2] http://lists.w3.org/Archives/Public/public-html-media/2014Dec/0012.html

Matt